[Prior Art]
[Patent Reference 1] Japanese Unexamined Patent Publication No. 108456/1992A (Tokkai-hei 4-108456)
[Patent Reference 2] Japanese Patent publication No.3300155 B
A guide wire is generally inserted into a blood vessel proceeding catheter in order to guide the catheter to a target point. And the tip is formed into a J-shape or loop-shape so that the tip can be inserted smoothly into the blood vessel which might wind hard. Such a guide wire has a core tapered toward the tip end, and a coil attached on the core wire whole or at the tip end potion partially. The core wire has a suitable strength or rigidity so that the core wire can be remotely controlled from user's hand side, and has flexibility so as not to injury the vein or blood vessel.
A typical prior art of guide wire is shown in FIG. 11. The guide wire 100 has a core 101 made of stainless steel, carbon steel, Ti—Ni wire, and the like, and a coil 102 made of stainless steel, platinum, platinum alloy, tungsten, and the like, and has a flexible carved tip end 100a. 
In the Patent reference 1, as shown in FIG. 12a there is described a process for producing a guide wire by curling the tip end 101a of a core 101 into J shape previously, curling the corresponding portion 102a coil (spring member) 102 into J-shape, and thereafter combining those members (see page 2, left upper column of the publication). Further, there is proposed another producing process, as shown in FIG. 12b, by curl-forming a coil into J-shape previously only and, then combining a straight coil 102.
In Patent Reference 1, it is stated that the former process is troublesome since curvature of the core 101 and coil 102 are not precisely accorded, and the latter process can not produce a guide wire with precisely curved shape. And Patent reference 1 proposes to form the coil 102 with a sparse portion in number of turns in a portion corresponding to the curved portion 101a of the core 101, with keeping the latter process basically. And by using the producing process, an elastic deformation of the J-shaped portion 101a due to the elastic force of the coil 102 can be controlled. As material of the core 101 and the coil 102, superelastic metal such as Ni—Ti alloy is mentioned other than stainless steel.
Besides, Patent Reference 2, as shown in FIG. 13 discloses a producing process by combining a straight core 101 and a straight coil 102 previously, inserting the combination 103 into a die 105 having J-shaped groove 104, attaching a lid 106 on the die, and performing heat-treatment to form a curved shape. In this producing process, the material of the core 101 is stainless steel or carbon steel, and the material of the coil 102 is stainless steel, platinum, platinum, gold or tungsten.